Adaptive adversaries such as terrorists, insurgents, and criminal networks as well as states will increasingly resort to irregular forms of warfare as effective ways to challenge conventional military powers. Advances in technology and other trends in the environment will render such irregular threats ever more lethal, capable of producing widespread chaos, and otherwise difficult to counter. [IW activities include]: counterterrorism, unconventional warfare, foreign internal defense, counterinsurgency, and stability operations. (Irregular Warfare Joint Operating Concept, 2010)

Due to the increasing availability of technical information and dual-use equipment on the global economy, it is correspondingly increasingly possible for sub-state groups to develop improvised weapons using chemical, biological, and radiological hazards. Although these weapons may not be as effective or deadly as those designed by a nation-state, they can cause significant disruption to unprotected civilians and government operations. The counter-WMD aspect in IW is different from Homeland Defense/Civil Support in that the U.S. military conducts offensive operations (not just response) against sub-state groups or states using irregular warfare tactics, either of which may have CBRN weapons. To effectively counter these groups, the Joint Force must both understand the unique nature of these threats and adopt collaborative frameworks to understand, plan, act, assess, and adapt in concert with USG interagency and multinational partners as well as the host nation.

Below is a list of documents that provide more information on Irregular Warfare.